Elevator safety device



:F. HYMANS ELEVATOR SAFETY DEVI GE March 14, 1939.

3 Sheets-Sheet 1 Filed July 2, 1937 ATTORNEY F. HYMANS ELEVATOR SAFETY DEVICE Filed July 2, 1937 SSheets-Sheet 2 INVENTOR ATTORNEY March 14, 1939. F. HYMANS ELEVATOR SAFETY DEVICE Filed y 2, 1957 ATTORNEY ih gmwaaarw F 4 INVENTOR "Fig.5

Patented Mar. 14, 1939 UNITED STATES PATENT OFFICE ELEVATOR SAFETY DEVICE Application July 2, 1937, Serial No. 151,589

7 Claims.

The invention relates to safety apparatus for elevators and especially to that type of safety device or brake which acts under emergency conditions to bring the elevator car or counterweight to a stop during its downward movement, by applying means to the guide rail to exert a braking action.

In the normal operation of elevators, the rail engaging means of such safety devices do not engage the guide rails. Upon the occurrence of v emergency conditions where it becomes imperative that the system be brought to an immediate stop, such as parting of the hoisting ropes or overspeed due to other conditions, mechanism comes into immediate operation to effect the application of the rail'engaging means to the guide rails. It is important that the force with which the-rail engaging means engage the rails be sufficient to effect a stop which is as quick as is consistent with the comfort and safety of passengers within the car and which will not cause damage to apparatus. Also, it is desirable that the release of the rail engaging means from the guide rail may be readily effected.

It is an object of the invention to provide safety apparatus of the above character which is of simple construction, reliable in operation and which may be safely operated a considerable number of times without any replacements.

The invention involves the provision of a U spring spanning the rail engaging means forexerting the force applying the rail engaging means to the guide rail. As the rail engaging means is applied to the rail, the legs of the U :5 spring are gradually spread, thereby gradually increasing the force with which the rail engaging means grips the rail. Preferably, the mechanism is arranged so that the force with which the rail engaging means is applied to the rail 40 becomes constant upon reaching a certain predetermined amount.

Features and advantages of the invention will become apparent from the following description and appended claims. In the drawings:

Figure l is a schematic representation of an elevator system embodying elevator safety apparatus in accordance with the invention, the safety apparatus being illustrated as applied to the elevator car;

Figure 2 is an enlarged end view in somewhat diagrammatic form of the safety apparatus shown in Figure l;

55 Figure 3 is a plan view with parts in section on a further enlarged scale of the rail clamp shown in Figure 2; I I

Figure 4 is a side view of the rail clamp shown in Figure 3 with parts broken away; and

Figure 5 is a view in perspective of the rail 5 clamp 01' the preceding figures.

Reference will first be had to Figure 2, in which the mechanism is somewhat diagrammatically shown for illustrating principles of operation of the invention. The rail clamp for 10 only one of the guiderails is shown in this figure. The operating parts of the rail clamp are supported by a mounting block 85 secured to the safety channels 81 of the car framework. The shoes for engaging the guide rail are in the form 15 of wedges 63 and 64, one on each side of the guide rail. These wedges are normally disengaged from the rail. To apply them to the rail, they are pulled upwardly by rods 64 and 62. As they move upwardly, these wedges slide against 20 and roll on rollers 68 mounted in frames 69. The rollers, in turn, are arranged to roll on the inclined surfaces of guide blocks 80. The rollers are biased into position against stops 94 on mounting block 85 by springs 95 arranged be- 25 tween the mounting block and the bottoms of frames 69. The mounting block is arranged to guide the guide blocks 80 for movement normal to the side faces of the guide rail and provides stops [Hi to limit their inward movement. A U 30 spring H5 spans the guide blocks, this spring being under an initial pressure. Swivel joints are provided between blocks 80 and the legs of the U spring, the spring being supported at its yoke on a portion of mounting block 85.

' Assume that the elevator car ismoving downwardly. Upon a pull being exerted on rods iii and 62, the wedges 63 and 64 are'lifted. During the initial part of their movement, they slide upon rollers 68. This continues until the wedges, 40 due to their being pushed inwardly by the rollers, engage the sides of the guide rail. From this point on, the wedges roll on the rollers until they are brought to a stop by the mounting block 85.

As soon as the wedges start to roll on the rollers, the rollers in turn roll on the inclined surfaces of the guide blocks 80, lifting their frames 69 upwardly against the force of springs 95. As this movement takes place, the guide blocks are forced outwardly by the wedges against the force of the U spring H5 so that the force with which the wedges are applied to the guide rail is gradually increased until the wedges are brought to a stop by the mounting block. Due to the wedges gripping the rail, the elevator car is gradually reta rded by an increasing force which becomes constant as the wedges are brought to a stop by the mounting block. In this way the elevator car clined surface of guide blocks 88. This permits inward movement of the guide blocks, gradually decreasing the force with which the wedges are applied to the guide rail and finally releasing the wedges, whereupon the parts assume their positions illustrated in Figure 2.

Before describing details of a specific embodiment of the invention, reference will be had to Figure 1 for a general understanding of the elevator system to which the safety apparatus may be applied. Hoisting ropes II for the car and counterweight pass over the hoistingv drum I2 at the top of the elevator shaft. This drum is driven by means of a hoisting motor l3 to effect the raising and lowering of the car and counterweight. An electromagnetic brake I4 is employed to aid in bringing the motor to a stop and to hold the car while at rest. Guide rails ii are provided for the elevator car. The bottom guide shoes for the car are designated l6 while the top guide shoes are designated l'l. These guide shoes cooperate with the guide rails to guide the car in its movement up and down the elevator shaft.

A governor rope 2| extends around a governor sheave 22 at the top and a tensioning sheave 23 at the bottom of the hatchway, the tensioning sheave being provided with weights 24. Governor sheave 22 is mounted on a governor shaft 25, which is geared to spindle 26. The governor is illustrated as of the fly ball type, being provided with centrifugal weights 21, weight arms 28, sleeve 30, connecting links 3|, and resisting spring 32. Two eccentric clutches 33 and 34 are rotatably mounted on shafts 35 and 38 and are caused to move together by spur gear segments 31 and 38. Shaft 35 is mounted on movable rod 40, the rod being mounted in a frame 4|. A spring 42, abutting against a portion of the frame and the collar 44 on the rod, biases clutch 33 toward clutch 34, this spring determining the pressure with which rope 2| is gripped by the clutches as it passes between them when the clutches are released. Thus governor rope 2| is allowed to slide through clutches 33 and 34 but at the same time exerts a pull suflicient to apply the safety. A spring pressed latch, engages a projecting portion of clutch 34 to prevent application of the clutches until the governor, acting through links 48 and 41, effects a releaseof the latch.

The ends of the governor rope are secured in rope'sockets which are pivotally connected to one arm 48 of a bell crank lever 58. This lever is mounted on a pivot pin 89 extending through the upper cross channels 5! of the car framework. The other arm 52 of the bell crank lever is connected by a link 53 to an arm 54 of an additional bell crank lever 55. This lever is likewise mounted on a pivot'pin 56 extending through channels 5|. These levers are for actuation by the governor rope when the rope is gripped by the governor clutches to apply the rail clamps to the guide rails. In the positions illustrated in Figure 1, these levers are in non-brake-applying positions. They are latched in these positions by means of a link 51 pivoted to arm 52 of lever 58 and yieldably held between a fixed pin and a movable pin by a spring 58, these pins extending into depressions formed in the link.

Each of pins 48 and 56, on the other side of channels 5|, has secured thereto another lever similar to levers and respectively. The additional lever 60 on pin 49 is shown in Figure 2. Each of these four levers has an operating rod secured thereto, these rods being actuated by the levers to apply the rail clamps to the guide rails. The arrangement is the same for both guide rails.

JTherefore, the arrangement for only one guide rail will be described in detail.

Referring now to Figures 2, 3, 4 and 5, the operating rods GI and 62 extend from levers 50 and 50 to wedges 83 and 84 of the rail clamp, to which they are connected by bolts 85. These wedges are arranged one on each side of the guide rail and are normally disengaged therefrom but are adapted to be moved into engagement with the'side faces of the guide rail upon the actuation of their operating rods by levers 50 and 60. The arrangement of the guide clamp on the two sides of the guide rail is symmetrical so that the construction ofonly one side, the side including wedge 64, will be described in detail.

The inner edge 66 of wedge 64 facing the guide rail is parallel to the side face thereof. The outer edge 61 of the wedge is arranged at an angle to the guide rail. A plurality of rollers 68 are provided for the outer edge of the wedge to slide and roll upon when it is pulled upwardly by its operating rod in the operation of the clamp. The rollers 68 are rotatably mounted on pins 10 extending between two shallow channels II and 12. The channels are secured to spacing blocks 13 and 14 to form a frame 69, these blocks being of a width to permit rotation of the rollers. Slots 15 and 16 are provided in the sides'of the wedge to receive the inner flanges of these channels. These slots are parallel to the outer edge of the wedge and form a guide for the wedge in its movement relative to the rollers. The outer flanges of the channels extend into slots I1 and 18 formed on opposite sides of a guide block 80.

. This guide block isalso wedge shaped, its inner edge, 8| being parallel to the outer edge of the wedge. The slots TI and 18 in the guide block are parallel to face 8| and thus act to guide frame 69.

The guide block 88 and the, corresponding guide block on the other side of the guide rail are positioned between two plates 83 and 84 of a mounting block 85. The upper plate 83 is secured as by bolts 85 to the flanges of the safety channels 81 of the car framework. A slot 89 is provided in the plate through which the guide rail extends, ample clearance being provided so that the rail does not strike the plate during movement of the car. Plate 84 is joined to upper plate 83 by means of cross ribs 88 and 90. Another plate 9| is arranged beneath plate 84 and is joined thereto by means of cross ribs 92 and 83 aligned with cross ribs 88 and 90. This lower plate Si is for mounting the lower guide shoes as indicated in Figure 1.

When the rail clamp is not applied, the lowermost one of the rollers 68 on each side of the guide rail rests on the upper surface of a portion of intermediate plate 84, these portions of the plate forming stops 94 to limit the downward movement of frames 69. The frames are biased into these positions by compression springs 95. Each of these springs is arranged on a rod 96 and extends between the bottom of plate 84 and the bottom spacing block I4 of the frame. The rod extends downwardly through an aperture 91 formed in block I4. Near its top the rod has a washer 98 secured thereto soas to cause the rod to be supported by the spring. Above this washer the end of the rod extends into a locating aperture (not shown) in the bottom of plate 84. When the rail clamp is not applied, wedges 53 and 64 rest on the blocks I4 of frames 69.

The upper plate 83 is provided with a pair of slots I88, one on each side of the guide rail in the bottom thereof, while the plate 84 is provided with a pair of slots IflI, one on each side of the guide rail in the top thereof. These slots and are for receiving keys I82 provided on the top and bottom of the guide blocks to guide the blocks for movement in the direction perpendicular to the sides of the guide rail. The slots I08 in upper plate 83 extend through lugs I03 formed on the bottom of plate 83 at the guide rail slot 89. Blocks'l04 are secured to the bottom of these lugs by bolts I05, keys I05 being formed on the blocks for extending into slots I80 for properly locating the'seblocks. The blocks I04 are in the path of movement of wedges 63 and 64 and serve as stops to limit the upward movement of the wedges with respect to the mounting block 85 when the rail clamp is applied to the guide rail.

The upper plate 83 is provided with an additional pair of slots II" in the bottom thereof, one'on each side of the guide rail, these additional slots being crosswise with respect to slots I80. Similarly, intermediate plate 84 is also provided with a pair of additional slots I08, one on each side of the guide rail, extending crosswise with respect to slots IOI. In each of these slots is secured, as by bolt, an enlogated block H0. The top ones of these blocks extend into slots III formed in the top of guide blocks 80. The upper blocks IlIl cooperate with the outer sides of slots II I and the lower blocks III] cooperate with shoulders II2 formed on the bottoms of the guide blocks 80 to limit the inward movement of these guide blocks.

The guide blocks 88 are spanned by a U spring H5. The legs II6 of this spring are supported by the guide blocks 88 through the intermediary of bolts II'I secured to the legs and having rounded heads IIB extending into sockets I20 of the corresponding contour formed in the outer edges of the guide blocks, thereby providing swivel connections. Spacing washers 9 may be provided between the heads H8 and the legs of the U spring to adjust for the desired initial force exerted by the spring on the guide blocks, the amount of initial force being dependent upon the dimensions of the parts and the material of the spring. The yoke I2I of the spring is supported by a lug I22 formed as a rearward extension of cross ribs88 and 92.

In operation, the elevator car is caused to move up and down the hatchway by motor I3, the car transmitting motion to the governor through governor rope 2|. So long as the elevator runs at a speed less than the predetermined speed for which the governor is set to cause operation of clutches 33 and 34, no relative motion takes place between the car and the governor rope. In the event that thecar in its downward motion exceeds this predetermined speed, the governor operates to release latch 45, allowing clutches 33 and 34 to fall by gravity and grip rope 2|. This gripping action retards movement of the rope, thereby lifting arm 48 of bell crank lever 50 and pushing link 51 out of the position in which it is held by spring 58. Lever 58 acts through rod 53 to swing bell crank lever 55 clockwise. These levers cause corresponding movement of the levers on the other side of channels 5| in the car framework. This movement of these levers lifts the rods 6| and 82 to pull the wedges 63 and 64 of the rail clamps upwardly between the guide blocks 80. The wedges of each rail clamp in their initial movement slide on therollers 68 on each side of the guide rail until they are forced into engagement with-the side faces of the guide rail. From this point on, the wedges roll on the rollers and the rollers in turn roll on the inclined surfaces of guide blocks 80. As this movement takes place, the guide blocks are forced outwardly against the force of the U spring II5. This increases the force exerted by the U spring on the guide blocks which increases the force with which the wedges grip the rail. This increase in force continues until the wedges strike their stops I84. When this point is reached, the force with which the wedges grip the rail becomes constant. The above described action takes place very rapidly so that when an emergency condition arises requiring operation of the safety apparatus to stop the car, the rail clamps are quickly applied. The gripping'of the rail as above set forth gradually dissipates the kinetic energy of the elevator car, causing it to come smoothly to rest in a suitable distance without excessive deceleration. The elasticity of the U spring enables the rail clamp to adjust itself to any unevenness of the guide rail, obviating any undue stresses or abrupt stops. The force with which the wedges grip the rail may be varied to suit the requirements of different installations by varying the thickness of stops I 84.

When it is desired to release the rail clamps from the guide rail, the hoisting motor is energized so as to move the car in the up direction. As this movement takes place, the wedges 63 and 64 of each rail clamp remain stationary on the rail owing to the frictional force between the wedges and the rail. The rollers 68 roll on the inclined surfaces of the wedge as the mounting block 85 is moved upwardly by the car, permitting the guide blocks 88 to be moved inwardly by the U spring, thereby diminishing the force exerted by this spring on the wedges. This continues until the guide blocks are brought to a stop against their stops H0, whereupon the wedges 63 and 84 are released. The springs 95 return the roller frames 68 to their lowermost position and the wedges are brought to rest against the spacing blocks I4 of the frames.

The rail clampsare now in their disengaged conditions. The manual resetting of the governor jaws 33 and 34 and the setting of link 51 in position to be held by spring 58 places the mechanism in condition for another operation.

Although the safety apparatus has been described as applied to an elevator car, it is to be understood that it may equally as well be applied to the counterweight. understood that the rail clamps may be arranged to be operated under emergency conditions other than overspeed or in addition to overspeed. Also,

It is to be further the arrangement of the operating mechanism for the rail clamps may be varied, this including not only the mechanism for lifting the wedges but also the governor operated apparatus. In

ing sense.

What is claimed is:

1. In an elevator system having a body movable in the elevator hatchway and a rail extending longitudinally of the hatchway, a safety device for said movable body, said safety device comprising; mounting means carried by said body; a member slidably supported by said mounting means for movement toward and away from said rail; means for gripping said rail: a U spring spanning said rail gripping means. one leg of said U spring being supported by said member; and means operable to apply said gripping means to said rail during downward movement of said body, said gripping means, upon being applied, acting to spread the legs of said U spring.

2. In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said safety device comprising; a pair of rail gripping members, one on each side of the rail; means secured to said movable body forsupporting said members; a U spring spanning said gripping members, the yoke of said U spring being supported by said supporting means; means oper able during downward movement of said body to apply said members to said guide rail; and means interposed between said members and said spring, supporting the legs of said spring and operable by said members upon their engaging said rail to spread the legs of said U spring.

3. In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said safety device comprising; a pair of wedges, one on each side of the rail; guide means for each wedge; means secured to said movable body for mounting said guide means; a U spring spanning said guide means; and means operable during downward movement of said body to lift said wedges with respect to said mounting means, said wedges upon being lifted being guided by said guide means into position wedged between their guide means and said guide rail, said U spring acting to apply said wedges to said rail with sufllcient force to bring the movable body to a sto 4 In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said safety device comprising; a pair of wedges, one on each side of the rail and normally disengaged therefrom; guide means for each wedge; means secured to said movable body for mounting said guide means, said mounting means being arranged to guide said guide means toward and away from said rail; 9. U spring spanning said guide means; and means operable during downward movement of said body to lift said wedges with respect to said mounting means, said wedges upon being lifted being' guided by said guide means into engagement with said guide rail and thereafter acting through said guide means against the force of said U spring to grip the rail, said mounting means including stops for limiting the amount of upward movement of said wedges to thereby limit the retarding force.

5. In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said ning said guide blocks; and means operable during downward movement of said body to lift said wedges with respect to said mounting block, said wedges upon being lifted being guided by said .guide blocks through said rollers into engagement with said guide rail and thereafter acting through said rollers and guide blocks against said U spring, said mounting block being provided with stops for limiting the amount of upward "movement of said wedges, the force exerted by said wedges in bringing said body to a stop being transmitted directly through said stops to said mounting block, said U spring taking only tlgie1 side thrust of applying said wedges to said r 6. In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said safety device comprising; a pair of wedges, one on each side of the rail and normally disengaged therefrom; a guide block for each wedge; a plurality of rollers between each wedge and its guide block; a mounting block for said guide blocks secured to said movable body, said mounting block having guides for guiding said guide blocks for movement in a direction normal to the faces of said guide rail, stops for limiting the inward movement of said guide blocks, and stops for limiting the upward movement of said wedges; a U spring spanning said guide blocks and exerting an initial pressure against them; and means operable during downward movement of said body to lift said wedges with respect to said mounting block, said wedges upon being lifted being guided by said guide blocks through said rollers into engagement with said guide rail and thereafter acting, until brought to a stop by engaging their stops, through said rollers and guide blocks to spread said U spring, thereby increasing the force with which they grip the rail to an amount suflicient to cause said body to be retarded and finally brought to a stop at a desired rate.

'I. In an elevator system having a body movable in the elevator hatchway and a guide rail for said body, a safety device for said body, said safety device comprising; a pair of wedges, one on each side of the rail and normally disengaged therefrom, the inside edge of each wedge being parallel to the side of the guide rail which it faces and the outside edge being at an angle thereto taken on a line intersecting said rail at a point above; a guide block for each wedge, each guide block having its inner edge parallel to the outer edge of the wedge for which it is provided; a plurality of rollers between each wedge and its guide block; a mounting block for said guide blocks secured to said movable body, said mounting block having guides for guiding said guide blocks for movement in a direction normal to the faces 0! said guide rail, stops for limiting the inward movement 0! said guide blocks, and stops for limiting the upward movement of said wedges;- a U spring spanning said guide blocks; a swivel connection between each guide block and the leg. of said spring adjacent thereto, said spring being supported by said swivel connections and said mounting block and exerting an initial pressure on said guide blocks; and means operable during downward movement 01' said bodytoliitsaidwedgeswithrespecttosaid mounting block, said wedges upon being lifted being guided by said guide blocks through said rollers into engagement with said guide rail and thereafter acting, until brought to a stop by engaging their stops, through said rollers and guide blocks tospread said U spring,- thereby increasing the force with which they grip the rail to an amount suiiicient to cause said body to be retarded and sired rate.

FREDERICK HYMANS.

finally brought to a stop at a de- 

